Tuberositriletes sp .

(Fig. 6H, L, M)

OCCURRENCE. — Ashikajima Fm (rare).

DESCRIPTION

Trilete microspore. Amb triangular with concave sides. The laesurae extend to the 3/4 of the spore radius. On the proximal face, the contact area is psilate, followed by one row of big welded verrucae (2-4 µm high, 2.5-5 µm in basal diameter) near the equator. The distal face is ornamented by welded and wavy rugulae, which are topped by verrucae. The rugulae are separated by small irregular spaces that can connect. Equatorial diameter = 28 µm.

BOTANICAL AFFINITIES

Filicopsida.